Taking Photos of Knife Edges

Visual inspection of the knife's edge is an important part of sharpening a knife. Pre-sharpening is important to see what you are up against. Post-sharpening is important as it helps one know how good of a job one did. To that end I have been experimenting with taking photographs with my smart phone.

Pitted Blade on Shun Knife

As issued my smart phone can't take a picture of a knife edge. A real closeup photograph like the picture above is called a macro, and the camera or the lens needs to be designed for macro photography.

I have a small handheld magnifier that I use to inspect knives, and to take this photograph I held the magnifier up to the camera lens. I think it worked pretty well! It does take three hands to hold all elements in position and position everything in the proper light, and dealing with the very small 'focus' window is almost insurmountable — but other than that it's a piece of cake.

Magnified View of Dull Knife Edge

Here is a closeup of a dull knife. I wanted to capture the 'glint' of light that one sees on a dull knife edge.

As a knife is used, the sharp edge gradually rounds. A sharp edge will not reflect light, the more rounded (dull) the edge becomes the more light that is reflected.

Magnified View of a Sharp Knife Blade

Here is the same knife after I sharpened it. A sharp edge reflects no light.